You can get there from here.

1. Make hot tea as usual.
2. Drink half of it, as you were intending.
3. Refill your mug, and place on top of magnet box.
4. Refill liquid nitrogen into magnet box, quickly cooling top of box.
   
5. Enjoy a rapidly chilled drink.
   

Note: I might have mentioned this before, but liquid nitrogen (which is essentially liquid air, as air is 80% nitrogen) costs less than $2 a gallon. Whole milk, by contrast costs almost $4/gal.